The carbonylation of unsaturated compounds, particularly unsaturated hydrocarbons, is broadly known in the art. European Patent 55,875 describes a process for carbonylation of an olefin in the presence of water and optionally alcohol or acid, to produce acids, esters or anhydrides. This process employs a halide-free palladium catalyst and a tertiary phosphine with at least one aliphatic substituent. A similar process is disclosed by European Patent 106,379 where the catalyst system contains at least a minimum amount of triarylphosphine and a non-hydrohalogenic strong acid. European Patent Application 190,473 discloses a similar process wherein the catalyst system comprises a divalent palladium compound, at least a 15-fold excess of organic phosphine and certain strong acid. European Patent Application 198,521 is directed to carbonylation of conjugated dienes in the presence of water or alcohol, an aprotic solvent and a catalyst system containing an excess of tertiary phosphine and at least one mol of hydrogen chloride per mol of phosphine. Yet another similar process is disclosed in European Patent Application 235,864 wherein the catalyst system contains non-carboxylic acid having a pKa greater than 2 and/or a sterically hindered carboxylic acid having a pKa below 4.5. European Patent Application 282,142 discloses the inclusion of a phosphine having a heterocyclic substituent in the catalyst system.
The carbonylation of an unsaturated alcohol in the presence of acid and a bimetallic catalyst system is shown by U.S. Pat. No. 4,634,780. The product is a lactone and apparently polymerization does not take place. Substitution of an unsaturated acid for the alcohol would lead to a cyclic anhydride if the reaction were analogous. Although such lactones or cyclic anhydrides could be polymerized by subsequent procedures, it would be of advantage to provide for carbonylation of unsaturated alcohols or acids which directly provides polymeric polyesters or polyanhydrides.